Abstract
Droplet interactions with compliant materials are familiar, but surprisingly complex processes of importance to the manufacturing, chemical, and garment industries. Despite progress—previous research indicates that mesoscopic substrate deformations can enhance droplet drying or slow down spreading dynamics—our understanding of how the intertwined effects of transient wetting phenomena and substrate deformation affect drying remains incomplete. Here we show that above a critical receding contact line speed during drying, a previously not observed wetting transition occurs. We employ 4D confocal reference-free traction force microscopy (cTFM) to quantify the transient displacement and stress fields with the needed resolution, revealing high and asymmetric local substrate deformations leading to contact line pinning, illustrating a rate-dependent wettability on viscoelastic solids. Our study has significance for understanding the liquid removal mechanism on compliant substrates and for the associated surface design considerations. The developed methodology paves the way to study complex dynamic compliant substrate phenomena.
Highlights
Droplet interactions with compliant materials are familiar, but surprisingly complex processes of importance to the manufacturing, chemical, and garment industries
For practical applications, understanding how droplets adhere, slide, and remove themselves from surfaces is of great fundamental importance, and numerous studies have investigated the physics of droplet motion and removal from rigid substrates and the diverse set of behavior for a range of liquid properties[10,11] and environmental conditions[12,13,14]
Notable works include Pu et al.[19] who investigated the effect of substrate viscoelasticity on the wetting and drying behavior of droplets and Lopes et al.[20] who showed that deformation near the contact line influences evaporation of a sessile droplet
Summary
Droplet interactions with compliant materials are familiar, but surprisingly complex processes of importance to the manufacturing, chemical, and garment industries. We investigate the mutual influence of substrate viscoelasticity and associated transient mesoscopic substrate deformations on droplet receding dynamics during drying for a range of environmental conditions and material compositions regulating the process For this purpose, we have advanced and tailored a high-speed four-dimensional confocal reference-free traction force microscopy (4D cTFM) method[35] (three spatial dimensions and time). A decrease in the apparent contact angle is to be understood in conjunction with the sharp inward bent of the wetting ridge apex, which acts to pin the contact line and gives rise to a wetting transition These findings are expected to have importance in a broad range of fields, impacting liquid retention/removal from compliant substrates and resolution of 3D printing of soft materials
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
